1. Field of the Invention
The present invention relates to a method of producing nano-sized lithium-cobalt oxide utilizing a flame spray pyrolysis. More particularly, this method is related to effectively producing nano-sized lithium-cobalt oxide as an electrode material for storing energy from an aqueous metal solution containing lithium and cobalt metallic salt by utilizing flame spray pyrolysis. Especially, the nano-sized lithium-cobalt oxide is verified to have the necessary super-electrochemical properties to act as the active material for a lithium ion battery.
2. Description of the Prior Art
Because lithium batteries are capable of providing high energy densities while maintaining a low weight, the lithium battery has become a major power source for most small portable electrical equipment beginning in the mid 1980s.
Recently, use of the lithium ion secondary battery, which is a type of lithium battery, has rapidly increased. The lithium ion secondary battery comprises a cathode, anode, organic electrolyte and organic separator. Lithium-cobalt oxide, when used as the active material, has the properties of excellent reversibility, low discharge rate, high capacity, high energy density and easy synthesis. Lithium-cobalt oxide is presently commercialized.
Even though the lithium ion secondary battery has a relatively longer life span of between charges, it is limited to 500 cycles of charging/discharging. Therefore, experiments are being conducted to develop new materials for a long life battery having a high operating voltage and a large capacity for charging/discharging with high efficiency.
In particular, nano-sized lithium-cobalt oxide developed for use in the lithium battery enables not only increasing the existing benefits of excellent specific energy and speed of charging/discharging, but also providing stabilization over many cycles when the lithium ion is performing the intercalation-deintercalation. Thus, it is anticipated that a battery made with nano-size electrode materials will provide have high efficiency with longer life spans than the presently commercialized battery made with 10 μm˜30 μm of lithium-cobalt oxide.
The methods suggested for producing nano-sized lithium-cobalt oxide employs the processes of zol-gel, dehydrofreezing evaporation, supercritical dehydration, supersonic hydrothermal synthesis and ultra sonic processing.
Furthermore, the process of solid states synthesis for producing the lithium-cobalt oxide is well known and is a simple and economical process. However, this process has difficulty producing micro-sized particles below 10 μm of the lithium-cobalt oxide due to coagulation arising from the non-uniform distribution of the particles, the non-cathode synthesis and solid phase reaction.